Re: From Amazon's denial
The story said Amazon had only found servers with the spy chips in their Chinese datacenter. Apple found it in a limited fashion as well. These weren't across the board "wow, we have to replace everything in all our datacenters".
It seems both companies do some very robust checking of the boards they are shipped, since it was noticed rather quickly. It goes without saying that 99.99% of companies don't even check the boards in their servers to look for a tiny component that doesn't belong. The main reason Amazon and Apple did was because like other major 'cloud' companies such as Google, Facebook, Microsoft etc. they design their own boards, and want to verify what they are shipped matches their design.
That's why the spy chip was apparently disguised to look like a passive component, hoping it would be ignored as something to address RF or electrical issues.